苏北溱潼凹陷的拉张量研究及构造运动强度分析   总被引：3，自引：0，他引：3  

施泽进  施央申 《大地构造与成矿学》1994,18(1):43-52

运用正演平衡剖面方法，本文对苏北溱潼凹陷三条剖面的演化过程进行了模拟，恢复计算出各断层各期次的伸展量，该箕状凹陷各发展阶段的拉张量以及对应于三期主要构造运动的拉张量。结果表明，构造运动具有延续性，仅在某些组段的表现更为强烈。在时空上，拉张活动具有很大的不均衡性，在凹陷的西南部，中部及东北部地区，拉张量及沉积特征均有很大差异，构造运动的强度也各不相同。  相似文献   

Nitrate in groundwater and N circulation in eastern Botswana   总被引：1，自引：0，他引：1  

E. Lagerstedt  G. Jacks  F. Sefe 《Environmental Geology》1994,23(1):60-64

Nitrate pollution due to deep leaching from pit latrines has caused water supply wells in eastern Botswana to exceed health limits concerning nitrate. It was deduced from the estimated intake of salt and protein by the population that, as an average, about 10 percent of the human nitrogen excretion is leached to the groundwater. This fraction was also found in southern India, where on-the-ground excretion is customary. The nitrogen circulation in general in the savanna ecosystem is not appreciably affected in spite of a large livestock density. Overall nitrate leaching is in the order of 1.5 kg N/ha/y, similar to that in another semiarid area in southern India. However, in India, there seems to be a more diffuse areal leaching from agriculture as well as from villages.Measures to minimize the nitrate leaching could be to plant deep-rooted trees adjacent to pit latrines or to use latrines that separate the urine from the faces for a more near-surface infiltration facilitating plant uptake. Measures to minimize leaching will also lessen the rick for bacterial pollution of the groundwater.  相似文献   

Dissolved carbon in pore waters from the carbonate barrier reef of Tahiti (French Polynesia) and its basalt basement     

R. Fichez  P. Harris  G. Cauwet  P. Dejardin 《Aquatic Geochemistry》1996,2(3):255-271

This paper deals with dissolved inorganic carbon (DIC) and organic carbon (DOC) in pore waters from a 150 m deep hole drilled through the carbonate barrier reef of Tahiti and its underlying basalt basement. Alkalinity-pH measurements were used to calculate the DIC species concentration, and DOC was analysed according to the high temperature catalytic oxidation technique. Salinity was used as a conservative tracer to help identify water origin and mixing within the hole. Water mixing, calcium carbonate dissolution and mineralization of organic carbon combined to form three distinct groups of pore water. In the deeper basalt layers, pore water with alkalinity of 1.4 meq kg^–1 pH of 7.6 and p(CO₂) of 1.2 mAtm was undersaturated with respect to both aragonite and calcite. In the intermediate carbonate layer, pore water with alkalinity of more than 2.0 meq kg^–1, pH of 7.70 and p(CO₂) of 1.4 mAtm was supersaturated with respect to both aragonite and calcite. The transition zone between those two groups extended between 80 and 100 m depth. The shift from aragonite undersaturation to supersaturation was mainly attributed to the mixing of undersaturated pore waters from the basalt basement with supersaturated pore waters from the overlaying limestone. In the top of the reef, inputs from a brackish water lens further increased p(CO₂) up to 5.6 times the atmospheric P(CO₂).  相似文献   

Comparison of Cu and Zn cycling in eutrophic lakes with oxic and anoxic hypolimnion     

HanBin Xue  René Gächter  Laura Sigg 《Aquatic Sciences - Research Across Boundaries》1997,59(2):176-189

Data on the cycling of Cu and Zn in two eutrophic lakes are presented: Lake Greifen that becomes seasonally anoxic in its hypolimnion and Lake Sempach that is aerated during winter and oxygenated during summer. They suggest that hypolimnetic oxygenation 1) enhances the release of copper from the sediment but 2) also accelerates the entrapment and deposition of Cu and Zn by freshly formed Mn- and Fe-oxides.  相似文献   

中国地下热水的基本类型和成因特征   总被引：12，自引：0，他引：12  

王东升  王经兰 《第四纪研究》1996,16(2):139-146

循环型地下热水的δＤ和δ¹⁸Ｏ具有类似于现代大气降水的线性关系和环境效应，其δＤ低于当地大气降水，据８０年代末检测其氛比值一般小于１，¹⁴Ｃ年龄逾２００００ａＢ．Ｐ．(华北)，这说明循环型地下热水起源于区域古大气降水，且补给期为冷湿的雨期。封存型地下热水中贫氘富钙的Ｃｌ－Ｃａ型烃矿床卤水，其δＤ和δ¹⁸Ｏ接近初生水值域，⁴⁰Ａｒ／³⁶Ａｒ值接近海岭型值域，反映水的一级起源──上地幔的脱水排气作用。  相似文献   

湖泊沉积物-水界面营养元素的生物地球化学作用和环境效应　Ⅰ.界面氮循环及其环境效应   总被引：7，自引：0，他引：7  

吴丰昌  万国江  黄荣贵 《矿物学报》1996,(4)

发生在沉积物-水界面的剧烈生物地球化学作用对沉积物和上覆水体具重要的环境效应，然而此方面研究很少。本文通过云贵高原四个湖泊湖水和孔隙水NH和NO剖面，沉积物柱芯不同结合态氮含量剖面分布，界面扩散通量，影响氮循环的因素及它们季节性变化规律等的对比研究，初步揭示了湖泊沉积物一水界面的氮循环及其环境效应。  相似文献   

National territorial planning at the turn of the 21st century     

Yong-Woong Kim 《GeoJournal》2001,53(1):5-15

In the early stages of economic development in Korea, national territorial planning was used as a policy tool to guide spatial structure and to provide physical infrastructure for urban and industrial development. Such a top-down approach was inevitable because Korea maintained the centralized political and government system until the early 1990s. Circumstances, however, have changed recently since the 1990s with progress in democratization and localization. In addition, forces of globalization are making significant impacts on the parameters of national territorial planning. Reflecting these changes in both internal and external conditions, the Fourth National Territorial Plan (2000–2020) has adopted a different approach from the past three territorial plans. This paper reviews the socio-economic background that necessitated such changes in approaches to national territorial planning. A major thrust of the Fourth Plan, a focus on emergent or anticipated planning issues in Korea, is discussed. Finally, the paper examines the rationale for long-term strategic planning in the highly fluctuating situation facing Korean society in the new century.  相似文献   

岩溶地层水文水井泡沫钻井压力和排量计算          下载免费PDF全文

郑秀华夏柏如  陈庆寿 《探矿工程》2001,(6):45-48

分析了岩溶地层水文水井施工中,泡沫实现平衡压力或欠平衡压力钻井的原理及影响泡沫钻井有效井眼压力的因素,采用迭代法逆循环计算方法,计算井口压力和井口气液排量。  相似文献   

滇池微生物解磷与聚磷作用的实验研究及磷的现代沉积与微生物成矿作用   总被引：4，自引：0，他引：4  

东野脉兴  樊竹青  张灼  夏学惠  田升平  周建民 《吉林大学学报(地球科学版)》2003,33(3):282-289

滇池是世界上磷质来源最丰富的湖泊，是研究磷的现代沉积和微生物对磷循环作用及微生物成矿的天然场所。研究发现，滇池微生物种群和数量繁多，但能对磷溶解、转化、迁移、聚集、沉积的微生物主要有解磷菌和聚磷菌两类。这两类微生物与滇池磷的含量之间有一系列规律的相关性：在底泥磷高含量区域，解磷菌的种群和数量与底泥磷含量成负相关关系，与水体磷含量成正相关关系，而聚磷菌的种群和数量与底泥磷含量成正相关关系，与水体磷含量成负相关关系；在底泥磷低含量区域，上述相关性则相反。滇池中这种活着的微生物在自然环境条件下对磷的溶解、转化、迁移、聚集和沉积的作用，对古磷块岩微生物成矿说提供了可靠的依据，而且对以磷为限制性因子的湖、海、江河环境污染的防治提供了理论资料。  相似文献   

平衡损失下回归系数stein压缩估计的性质     

胡桂开  黄涛 《华东地质学院学报》2007,30(4):383-386

在平衡损失风险函数准则下,研究线性模型中回归系数的stein估计优于最小二乘估计(LS)的充分必要条件,然后在pitman closeness(PC)准则下比较了stein估计相对于最小二乘估计的优良性。  相似文献